Residual insecticides, inert dusts and botanicals for the protection of durable stored products against pest infestation in developing countries

Insect pests associated with durable grains and processed food cause considerable quantitative and qualitative losses throughout the world. Insect infestation can occur just prior to harvest, during storage in traditional storage structures, cribs, metal or concrete bins, and in warehouses, food handling facilities, retail grocery stores as well as in-transit. Many tools are available for managing insects associated with grains and processed food. Although pest management strategies are changing to meet consumer’s demand for food free of insecticide residues, address concerns about safety of insecticides to humans, delay insecticide resistance development in insects and comply with stricter insecticide regulations, the use of synthetic residual insecticides will continue to be a major component of stored-product pest management programmes. Selective use of residual insecticides requires a through understanding and evaluation of risks, costs and benefits. The use of plant and inert materials may be a safe, cost-effective and environmentally friendly method of grain preservation against pest infestation among low-resource poor farmers who store small amounts of grains. There is a dearth of information on the use of plant materials by rural farmers in Africa for stored-product protection. The most promising candidate plant materials for future utilization as grain protectants are Azadirachta, Acorus, Chenopodium, Eucalyptus, Mentha, Ocimum, Piper and Tetradenia together with vegetable oils from various sources. Neem is the only plant from which several commercial products have been developed worldwide. However, unlike synthetic insecticides these alternatives often do not provide effective or rapid suppression of pest populations and may not be effective against all species of pests. These alternatives are also more expensive than synthetic insecticides, and have not been tested extensively under field conditions in the tropics. This paper focuses on the current state of the utilization of residual insecticides, inert dusts and botanicals by resource-poor farmers for protection of durable stored produce against pest infestation in Africa. A major research priority is a well designed on-farm trials to validate the efficacy of botanicals and inert dusts for stored-product protection using standard procedures and formulations that can be transferred to other communities. Key words: Botanicals, Residual insecticides, Inert dusts, Grain storage, Storage pests, Stored product

Problems with use of medicines

No Abstract

Systemic transformative adaptation towards urban economic resilience

The socioeconomic impacts of the Covid-19 pandemic are likely to increase further across economies. There is increasing apprehension on the status of rail transport infrastructure megaprojects which are already complex and face many uncertainties and it is imperative to initiate a restoration coupled with support to be implemented in a timely manner. Investors continue to invest in rail megaprojects that run high risks of being over-scheduled and over-budgeted, which has raised the need to improve rail megaporjects and their investments in order to establish the economic base of any society. Hence it is vital to analyse the systemic risks in rail megaprojects given their complexity and uncertainty towards developing an efficient risk management framework. To improve the performance of the procurement of rail megaprojects, the present study conducts a detailed literature review to explore the key procurement risk indicators and critical success factors for public procurement of rail megaprojects. The key findings are used to develop an integrated approach towards a systemic transformative adaptation to enable the effective incorporation of the procurement risk management process into the planning and decision-making of rail megaprojects in the UK. This study develops a conceptual framework that indicates that one of the most critical enablers of improvement in the performance of procurement of rail megaprojects is by enabling a collaborative approach. This is a unique study that presents key procurement risk indicators and critical success factors to derive sustainability based enablers to improve the performance of the procurement process of rail megaprojects

Intersections of Identity and Sexual Violence on Campus: Centering Minoritized Students’ Experiences

Book Revie

Field evaluation of non-synthetic insecticides for the management of insect pests of okra Abelmoschus esculentus (L.) Moench in Ghana

In a two-year study, aqueous seed extracts of the neem tree Azadirachta indica A. Juss (Meliaceae) and Bacillus thurigiensis (Bt) were evaluated in the field for the management of pests of okra, Abelmoschus esculentus (L.) Moench. The aqueous neem seed extracts were applied at the rate of 30, 50, 75 and 100 g/l and B.thurigiensis was applied at the rate 1.0 g/l of water. Actellic 25 EC, a synthetic insecticide, was applied at the rate of 2 ml/l as standard check. Arthropod fauna on okra were sampled using traps, sweep nets, aspirators and handpicking. The nature of damage caused to the stems, leaves, flowers and fruit was assessed by visual observation. The major insect pests of okra collected were Podagrica uniformis Jac, Aphis gossypii Glov, Sylepta derogata (F.), Spodoptera litoralis Boisd, Prodenia litura (F.), Dysdercus superstitiosus (F.), Epilachna similis (F.), Bemisia tabaci (Genn.) and Zonocerus variegatus (F.). These pests were observed attacking mainly the leaves of okra. Some of the minor pests identified were Lagria villosa (F.), L. cuprina Thoms, Mylabris temporalis Wellni, M. trifasciata (Thumb.), Lapidognatha sp and Empoasca devastans (D.). Actellic, neem seed extract and Bt significantly reduced the population and damage caused by the major insect pests of okra recorded at Legon, Ghana compared to the untreated. Actellic and aqueous neem seed extracts were equally effective against the pests of okra and caused a significant reduction in insect damage to the leaves, flowers and fruit of the crop. There were no significant differences among the different dosages of neem seed extract on all the parameters assessed, with the exception of the final fruit yield. Actellic, neem extracts or Bt produced higher yield of marketable fruit of okra than untreated plants. Neem seed extract applied at the rate of 30 g/l of water to okra plants produced lower fruit yield than those treated with 50 g or more. Aqueous neem seed extracts and Bt can be used effectively by farmers as a component of integrated management of pests of okra in Ghana. Key words/phrases: Bacillus thurigiensis (Bt), insect pests, neem seed extract, non-synthetic insecticides, okra SINET: Ethiopian Journal of Science Vol.26(2) 2003: 145-15

Some aspects of the biology and behaviour of Sesamia nonagrioides botanephaga Tams and Bowden (Lepidoptera: Noctuidae), a major stem borer pest of maize in Southern Ghana

Studies were conducted on the stemborer, Sesamia nonagrioides botanephaga Tams and Bowden (Lepidoptera: Noctuidae), which is a pest of increasing importance on maize in Ghana, to elucidate some aspects of its biology and behaviour in southern Ghana. The pest was more abundant in the minor season than in the major season. The life cycle revealed 10 developmental stages, namely the egg, six larval instars, prepupa and pupa. A female S. n. botanephaga laid eggs within a period of 5 days. The eggs were deposited on the inner side of the leaf sheath fitting tightly onto the maize stem. The mated females laid more eggs per female (330 + 17.7 eggs) than the virgin females (268 + 9.2 eggs). The incubation period of the eggs was 5.23 + 0.03 (5-7) days. The mean larval duration was 29 days and the prepupal period lasted for 1–3 days. The first instar larvae dispersed within 1–3 days after hatching. The third, fourth, fifth, and sixth instar larvae fed actively on maize stalk producing large quantities of frass. The pupal period varied from 6 to 10 days. The life cycle was completed in an average of 35.2 (26-51) days. Adults of S. n. botanephaga lived for between 4–10 days. The adults reared in the laboratory showed a sex ratio of 2:3 (male : female), which was significantly different from the expected ratio (1:1). The implications of these findings are discussed in relation to the effective management of the pest in Ghana

Bioactivities of crude extracts of the candlewood Zanthoxylum xanthoxyloides Lam. (Rutaceae) against the cowpea beetle Callosobruchus maculatus (Walp)

The efficacy of petroleum-ether crude extracts of the candlewood, Zanthoxylum xanthoxyloides Lam. was assessed for their contact toxicity, feeding and oviposition deterrence to the cowpea beetle Callosobruchus maculatus (Walp). Percent mortality, number of progeny produced and damage caused to were dose– dependent. Root extracts was the most effective as toxicant to the beetles. The LD50 in 24 h topical application of root extracts was 4.98 μg. The LD50 (96 h toxicity in grain) suggests that root extract was highly toxic to C. maculatus. Development of eggs and larvae within grain kernels, as well as progeny emergence were significantly inhibited in treated grains. There were no progeny produced by C. maculatus in grains treated with dosage ³ 0.4 g per 100 g of grain. Root extracts provided the greatest protection of cowpea against feeding by C. maculatus with no observable feeding damage to grains treated with the highest dosages of the three materials. Extracts were repelled C. maculatus but with considerable variation in their repellent action. Z. xanthoxyloides contains phytochemicals, and crude extracts could be used as a botanical insecticide in alternative control strategies against C. maculatus. Keywords: Antifeedant, Bruchids, Botanical insecticides, Reproduction retardant, Toxicity. Int. J. Biol. Chem. Sci. Vol. 2 (3) 2008: pp. 316-32

Toxicity, growth regulatory and repellent activities of medicinal plant extracts on Musca domestica L. (Diptera: Muscidea)

Housefly, Musca domestica, is a major vector for many medical and veterinary pathogenic organisms. The development of naturally occurring insecticides, represent one of the most promising approachesfor their ecochemical control. Petroleum-ether extracts of Griffonia simplicifolia and Zanthoxylum xanthoxyloides were assessed for their toxicity, growth regulatory and repellency to the housefly. Percent mortality and index of repellency induced by the extracts against the insects were found to be dose-dependent. Seed extracts of G. simplicifolia and root extracts of Z. xanthoxyloides were the mosteffective as toxicants and repellents against the fly. The LD50 in 24 h topical application of seed extracts of G. simplicifolia and root extracts of Z. xanthoxyloides were 0.28 and 0.35 ìg, respectively. Seed extracts of G. simplicifolia evoked a very strong regulatory effect against the second larval instar of the housefly. The RD50 of crude extracts of G. simplicifolia and Z. xanthoxyloides against housefly ranged from 1.0 to 6.8 and 1.3 to 1.7 ìg cm–2, respectively. Extracts of the two plant species may be useful as insecticides for controlling the housefly and should be exploited as a component of integrated vector control strategies or could be useful in the search of new larvicidal naturalcompounds

Effect of Irrigation Management Methods on Growth, Grain Yield and Water Productivity of Three Lowland Rice (Oryza sativa L.) Varieties

It has been predicted that Ghana will face water shortage by the year 2025 due to increased demand of water resources from all sectors of the economy. Rice production will be negatively affected since rice consumes the highest amount of water in the agricultural sector. To develop a strategy to reduce water use for rice production while maintaining or increasing rice yield, a pot experiment was carried out in the screen house at Soil and Irrigation Research Centre - Kpong during 2016 and 2017 cropping seasons to determine the effect of irrigation management methods on growth, yield and water productivity of three rice varieties. A three by five (3 x 5) factorial experiment was laid out in a randomized complete block design and replicated six (6) times. The levels of the variety were: Agra (VA), Ex Baika (VB) and a hybrid (VH). Irrigation management methods included: continuous submergence (I1), alternate wet and dry soil condition (AWD) from transplanting to panicle initiation (PI) then submergence to harvest (I2), AWD from transplanting to booting then submergence to harvest (I3), AWD from transplanting to lowering then submergence to harvest (I4), and continuous AWD (I5). Results from the experiment revealed that, I3 saved 21.7% and 20.4% of water used when compared with I1 in 2016 and 2017, respectively however, these treatments produced similar growth and yield in both seasons. I3VH recorded 21.2% and 20.8% of water saved in 2016 and 2017, respectively however, it produced similar grain yield with I2VH and I1VH treatments in both seasons

Boundary Applicability of the Ghana’s Oil Block Fiscal Regimes

AbstractAttractiveness of fiscal regime has become more important in oil and gas investment decision than the rather geological prospectivity of the province. The terms and conditions contained in the fiscal system influence the investor’s evaluation of project. As Ghana determines to benefit greatly from the exploitation of the oil and gas resources, a robust fiscal system attractive in all economical and technical conditions needs to be designed. Ghana has recently become one of the frontiers in the oil and gas industry following its commercial discoveries of hydrocarbons in Deepwater Tano-Cape Three Point, the Jubilee field. Ghana’s oil industry is very young and some of the basins are under exploration surveillances waiting for commercial discoveries. Ghana’s Jubilee field uses various terms and conditions in her fiscal arrangement to govern the upstream operations. For continuous realisation of economic benefits to the State as well as the contractor, it is important the applicability of Ghana’s fiscal regime at varying boundary conditions of oil price and field reserves are evaluated. Discounted cash flow economic model which considers the major uncertainties was developed to evaluate the economic implications of the Jubilee field fiscal regime. Different price scenarios and varying field sizes were taken through rigorous sensitivity analysis. It was determined that for all field sizes considered at oil prices above $40/bbl, contractor’s NPVs are positive. The project take statistics are averagely around 64$40/bbl where the State’s take statistic is above 80% and contractor’s take below 20%. The State receives Additional Oil Entitlement(AOE) only when the oil price is above $40/bbl and the AOE increases steadily with the oil price for all the various field sizes. In general, the Jubilee field fiscal regime is fairly attractive and flexible and ensures stable shares of economic rents between the State and the contractor as the profitability of the field increases. Keywords: Reserves, Fiscal Regime, Cash Flow, Take Statistics, Net Present Valu